Unexpected synthesis of (trifluoroethyl)pyrimidines from the heterocyclisation of α-trifluoroacetylpropanenitriles

Some 4-trifluoromethyl-2-aminopyrimidines analogous to trimethoprim and 5-trifluoroethyl-2,4-diaminopyrimidines analogous to pyrimethamine were prepared from enamino(trifluoromethyl)ketones and α-trifluoroacetylpropanenitriles, respectively. A novel heterocyclisation between a trifluoromethylated β-ketonitrile and guanidine was described.